Looks like American soldiers are once again allowed to walk around London, after a brief period in which they were forbidden to do so right after the bombings. No such luck for the physicists here at Saclay -- word has come down from on high that nobody is allowed to travel to England for the time being, presumably out of fear of further attacks. This is quite a disruption, as the big SUSY 2005 conference is being held in Durham next week.

Any counter-terrorism experts out there are welcome to correct me, but this strategy seems exactly wrong. I would guess that the time right after an attack is the absolutely safest time to travel. Surely, everyone riding a bus or the Tube in London is going to be just as jumpy and suspicious in the weeks to come as Americans taking airplanes were after September 11. Not only would it be much harder to carry off an attack, but the terrorists undoubtedly know this themselves, and it seems unlikely that they would even try.

I won't even bother to point out that, even including the successful attacks that have already occurred, the likelihood of being killed by terrorists is completely negligible compared to more mundane forms of danger. Death by subway bombing is so dramatic and horrible that it's hard not to worry about it far out of proportion to the actual threat (much like comparing sharks to vending machines). So some bureaucrats in Paris (or wherever) will feel assured that they are doing their job if they prohibit scientists from traveling to Britain. After some time passes, they will decide that the danger has diminished, and we can resume talking about important things, like the predicted abundance of neutralino dark matter candidates in various supersymmetric extensions of the Standard Model.